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Limón-Hernández, C.; Macías, J. L. Volcanic hazards and risk perception at the "Zoque" community of Chapultenango: El Chichón volcano, Chiapas, México Geofísica Internacional, vol. 48, núm. 1, enero-marzo, 2009, pp. 113-132 Universidad Nacional Autónoma de México Distrito Federal, México

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Volcanic hazards and risk perception at the “Zoque” community of Chapultenango: El Chichón volcano, Chiapas, México

C. Limón-Hernández1 and J. L. Macías1* Departamento de Vulcanología, Instituto de Geofísica, Universidad Nacional Autónoma de México, Mexico City, Mexico

Received: November 9, 2007; accepted: July 9, 2008

Resumen Después de 22 años de la erupción de 1982 del Volcán Chichón, se realizó el primer estudio estadístico de los residentes de Chapultenango (10 km al este del volcán), para evaluar la percepción del peligro y riesgo volcánico. Se aplicaron dos métodos: entrevistas con 90 adultos que sobrevivieron la erupción y cuestionarios complementarios a 210 estudiantes que nacieron después de la erupción. Durante las entrevistas los adultos reconocieron los fenómenos naturales de la erupción de 1982, aunque sólo el 50% estaba lo suficientemente informado sobre los peligros volcánicos, de hecho, sólo el 12% de los entrevistados cree que el volcán podría hacer erupción otra vez. Los cuestionarios muestran que los estudiantes están mejor educados e informados ya que la mayoría cree que el volcán podría hacer erupción nuevamente y están consientes de los peligros que representa. En caso de una nueva erupción, los estudiantes abandonarían sus casas para poner a salvo su vida; de éstos, el 66% conoce las rutas de evacuación. Los resultados demostraron que los habitantes de Chapultenango, en particular los adultos, tienen una inadecuada percepción del peligro y riesgo volcánico. Encontramos que, no se han implementado programas gubernamentales de largo alcance para incrementar la concientización de la población sobre los peligros volcánicos ni se han desarrollado estrategias para su mitigación.

Palabras clave: Peligro volcánico, percepción del riesgo, preparación para emergencias, Chichón, Chiapas, México.

Abstract After 22 years of the 1982 eruption of El Chichón volcano, we conducted a statistically based survey of the residents of the community of Chapultenango (10 km east of the volcano) to assess their perception of volcano hazards and risk. The survey used: interviews with 90 adults who survived the 1982 eruption, and completion of questionnaires by 210 students, who were born after the eruption. While adult interviewees recognized the volcanic phenomena of the 1982 eruption, many remained poorly informed about volcanic hazards. Surprisingly, only 12% of the interviewees believe that the volcano could erupt again. The students are more educated and better informed, and most of them believe that the volcano could erupt again and are well aware of the hazards posed. In case of future eruption, of the students answered that they would abandon their homes to save their lives; 66% knew the evacuation routes. The results demonstrate that people of Chapultenango -particularly the older residents- have an inadequate perception of volcanic hazards and risk, despite proximity to an active volcano. Unfortunately, no long-term go- vernmental programs to increase public awareness of volcano hazards and to develop hazards-mitigation strategies have been implemented at Chapultenango or other localities surrounding the volcano.

Key words: Volcanic hazards, risk perception, preparedness, Chichón, Chiapas, México.

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Introduction perception and social aspects of volcanic eruptions have been conducted. Most of these studies were dedicated During the 20th century, Mexico has been affected to understand resilience (Paton et al., 2001; Tobin and by several volcanic eruptions of varying magnitude and Whiteford, 2002), vulnerability (Johnston et al., 2000), type. These eruptions include the 1913 Plinian eruption preparedness (Gregg et al., 2004), hazards (Robertson, of Colima (Saucedo, 1997; Saucedo et al., 2005), the 1994; Chester et al., 2002), risk management (Meztger birth of Parícutin from 1943 to 1952 (Flores, 1945), the et al., 1999; Pareschi et al., 2000; Magill and Blond 1956 eruption of Bárcena in the Revillagigedo islands 2005a; 2005b), risk assessment (Pomonis et al., 1999), (Richards, 1959), the 1982 eruption of El Chichón in risk perception (Johnston et al., 1999), and disasters Chiapas, southern Mexico (Espíndola et al., 2002), (Witham, 2005). Most of them employed questionnaires the phreatic eruptions of Tacaná in 1950 and 1986 and interviews to survey people. Until recently these types (Macías, 2007), the submarine eruption of Everman in of studies had been neglected in Mexico, but during the Socorro Island (Siebe et al., 1995), and the reawakening past decade such studies have been undertaken at: Colima volcano (Cuevas and Ceballos, 2001; Gavilanes et al., in December 1994 of Popocatépetl, whose eruption 2008); Popocatépetl volcano (Hernández, 2004; López- continues to present (Macías and Siebe, 2005). Of all Vázquez, 2009); and El Chichón (Limón-Hernández, these eruptions, the 1982 eruption of El Chichón volcano 2005). set an important landmark in volcanological studies in Mexico. The volcano reawakened after 550 years of In this paper, we present a social-science study of the repose with a violent explosion that killed more than “Zoque” community of Chapultenango, which is located 2,000 people, representing the worst volcanic disaster in about 10 km east of the volcano’s summit. Using survey Mexico (Tilling, 1989; Espíndola et al., 2000; Macías et interviews with witnesses of the eruption and survey al., 2003) and killing more people by pyroclastic surges questionnaires with students who were not born until and flows than any eruption since the 1951 eruption of after the eruption but who now live within the volcano’s Mount Lamington, New Guinea which killed some 2,492 reach, we assess the knowledge and awareness of the people (Taylor, 1958). Chapultenango villagers regarding volcanic hazards, risk perception (from a geographic point of view; Slovic, The eruption of El Chichón had tremendous local, 1987), and preparedness to confront a future eruption of El regional and global impacts. Locally, nine villages, Chichón. Results of the study are presented and discussed several hamlets, and 100 km2 of forest were destroyed in terms of two sample groups according to age (“adults” and the region’s hydrological network was abruptly and “students”). Finally, we compared these results with modified (Sigurdsson et al,. 1984; Macías et al., 2004). studies in other volcanoes in Mexico and elsewhere. Regionally, the eruption produced darkness during day time at the City of Villahermosa, located about 60 Geologic Background km NE of the volcano in the neighbor state of Tabasco, and ash fall in the Yucatan Peninsula (Varekamp, et al., El Chichón volcano (N17°21´30”, W93°13´48”; 1984). Globally, the eruption emitted 7 megatons of sulfur 1,100 m above sea level) is located in the northwestern dioxide gas into the atmosphere (Krueger, 1983; Matson, area of the Chiapas State in southern Mexico. El Chichón 1984), which produced aerosols that circumnavigated the represents the northwestern-most active volcano of Earth, causing measurable changes in the temperature of the Chiapanecan Volcanic Arc (CVA) (Damon and the Earth’s surface. Collectively, these effects attracted Montesinos, 1978), formed by the subduction of the the attention of volcanologists who studied the chemistry Cocos plate beneath the North American plate, at the of the rocks (Luhr et al., 1984; Rose et al., 1984; McGee Middle American Trench (Stoiber and Carr, 1973) (Fig. 1). El Chichón volcano is built upon a late Jurassic-early et al., 1987), the new formed crater lake (Casadevall et Cretaceous marine sequence and Tertiary sedimentary al., 1984), the pyroclastic deposits (Sigurdsson et al., rocks (Canul and Rocha, 1981; Duffield et al., 1984). On 1984; 1987), and the presence of anhydrite in the magmas top of these sedimentary rocks were extruded a 1.1 Ma (Luhr et al., 1984; Carroll and Rutherford, 1987; Luhr, trachybasalt, whose outcrops are located in the vicinity of 1990). These works dealt primarily with physical aspects Chapultenango (García-Palomo et al., 2004). The initial of the eruption, but a few social aspects of the eruption phases of volcanism at El Chichón began around 0.37 Ma were also studied, including migration of the population, ago (Layer et al., this issue), followed by the formation recovery or resettlement of towns, damage to crops and of the Somma crater some 0.21-0.27 Ma (Damon and forest, and effects of the acid rain (Cervantes-Borja et al., Montesinos, 1978; Duffieldet al., 1984) and the extrusion 1983; Báez-Jorge et al., 1985). of peripheral domes 0.22 and 0.09 Ma and Holocene activity (Layer et al., this issue). During the past decade, several studies concerning risk

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Fig. 1. Tectonic setting of southern Mexico and Central America showing the Cocos, North America and Caribbean plates. El Chichón volcano located in southern Mexico, represents the active volcano of the Chiapanecan Volcanic Arc (CVA). Other important volcanic and structural features are found in the Trans-Mexican Volcanic Belt (TMVB), and the Central America Volcanic Arc (CAVA). Other abbreviations are: OFZ = Orozco Fracture Zone, OGFZ = O’Gorman Fracture Zone, and TR = Tehuantepec Ridge.

Prior to the 1982 eruption, the volcano consisted of a 2 Holocene record (Espíndola et al., 2000), inhabitants of km-wide Somma crater containing a 1,230 m-high central the region in the months preceding the 1982 eruption were dome (Fig. 2A). The 1982 eruption destroyed the central not really aware that El Chichón represented an active dome and formed a 1 km-wide crater inside the Somma volcano, let alone a threat to their communities. However, crater (Espíndola et al., 2000) (Fig. 2B); this crater holds an oral legend says that Piowacwe an old lady, visited the a lake with active fumaroles, hot mud and small ponds villages around the volcano weeks and days prior to the of water (Casadevall et al., 1984; Taran et al., 1998; event announcing the eruption. Tassi et al., 2003; Capaccioni et al., 2004; Rouwet et al., 2004). The pyroclastic surges and flows produced by Canul and Rocha (1981) reported that residents heard the 1982 eruption stripped the vegetation cover from the explosions and felt earthquakes at El Chichón since volcano, revealing older pyroclastic deposits which were late 1980, and more intensively during 1981. These subsequently studied in the years following the eruption occurrences were reported by local inhabitants to the (Tilling et al., 1984; Macías, 1994; Espíndola et al., local and state authorities in January 1982 (Báez-Jorge 2000; Macías et al., 2003). During the past 8,000 years, et al., 1985), many weeks before the climatic phases of the volcano has erupted at least 11 times with eruptions the catastrophic eruptions in late March and early April, occurring at 550, 900, 1250, 1500, 1600, 1900, 2000, 1982. The frequency of noises produced by the explosions 2500, 3100, 3700 and 7700 yr BP. These eruptions have and earthquakes both increased during March and were been separated by dormant intervals varying form 100 to recorded by seismographs located at the Chicoasen 600 years (Espíndola et al., 2000). hydroelectrical power plant, under construction by the Comisión Federal de Electricidad. The seismographs Summary of the 1982 eruption indicated that on March 6, 30 earthquakes occurred during a 24 hour period. On March 27, 1982, the seismic activity Despite increased fumarolic activity of El Chichón peaked with 66 earthquakes over a four hour period. The in 1930 (Mullerried, 1933), and the volcano’s violent first explosion of the 1982 eruption occurred on March 28

115 Geofis. Int. 48 (1), 2008 at 20:38 hr local time and ended at 23:22 hours (Espíndola Protection Program. Therefore, during the first hours after et al., 2002). This eruption partially destroyed the central the eruption an atmosphere of chaos and disorientation dome and produced an eruptive column that reached prevailed among these groups. Early in the human 27 km in height in 40 minutes. The volcanic cloud was response to the eruption, most people tried to escape by subsequently transported by stratospheric winds to the foot to the nearest towns and afterwards to larger towns NE. The dispersed ash fall covered 30,000 km2 of land, and cities. People living on the western side of the volcano including several towns among which the most important escaped towards Ostuacán and those living on the eastern were Francisco León, Volcán Chichonal, Esquipula side toward Chapultenango, Ixtacomitán, Tectuapán and Guayabal, Nicapa, Ixtacomitán, Chapultenango, Tectua- Pichucalco. However, ash fall reached these towns and the pán, Ostuacán, and Pichucalco (Báez-Jorge et al., 1985). displaced people moved by increments further northward That same day distal ash fall also affected the states of to Villahermosa, Tabasco or southward to Tuxtla Gutierrez Chiapas, Tabasco, Campeche and some areas of Oaxaca, in the State of Chiapas. In contrast, many people remained Veracruz and Puebla (Espíndola et al., 2002). at their homes close to the volcano during that first night of the eruption, despite the inherent dangers of doing so.

The next day (March 29), the Army secured a zone around the volcano and implemented its emergency plan against disasters called —DNIII (Desastres Naturales III; replaced by the current DN-III-E)— to manage the crisis (SDN, 1983). The Army forced 45,000 people to abandon their homes and land (Macías and Aguirre, 2006). Between March 29 and April 3, activity at the volcano remained low, but increased dramatically the following day. On April 4 at 7:30 pm, the most violent of all of the 1982 explosions of El Chichón occurred, accompanied by an increase in seismic activity. This climactic phase of the eruption involved hydromagmatic explosions, which completely destroyed the central dome. Pyroclastic surges and flows swept outwards from the crater. These pyroclastic flows were followed by the development of a phreatoplinian column that reached 32 km in height and was dispersed to the NE by stratospheric winds (Carey et al., 1986).

Pyroclastic surges and flows reached as far as 10 km from the crater, affecting an approximated area of 100 km2, where everything was completely flattened and barren (Fig. 3A-B). Beyond this zone, another zone covering some 150 km2 was affected by falling ash, which caused roofs of buildings to collapse (Figs. 3C, and 4A-B). Collectively, these two zones included 35,433 hectares and 29,321 of Fig. 2. A) Aerial view of El Chichón volcano prior to the 1982 them were severely damaged. Within the area affected by eruption, showing a central dome within the Somma crater. Pho- the eruption lived ca.approximately 6,000 people (INEGI, tograph by Rene Canúl in 1981. B) Aerial view of the volcano, 1997), of whom about 2,000 were killed by the eruption. showing the SW dome, Somma crater, and an inner 1-km wide Water supplies in both zones were polluted and most crater, excavated during the 1982 eruption by destruction of the animals perished (Báez-Jorge et al., 1985). The villages central dome. Photograph by Federico Fregoso, May 1982. that were completely or partially destroyed within the two zones were: Volcán Chichonal, Esquipula Guayabal, San This eruption surprised the scientific community, the Pedro Yaspac, Guadalupe Victoria, Carmen Tonapac, and local and federal authorities and the local population, Vicente Guerrero in Chapultenango county; El Naranjo, despite the fact that they were all aware of the precursors Volcán, Francisco León, Trinidad, San Antonio, San Isidro to the eruption. At that time, Mexico neither had a Tanchichal, Agua Tibia and San Juan Bosco in Francisco Scientific Committee to evaluate the eruption nor a Civil León county (Figs. 3 and 4).

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Fig. 3. A) Digital elevation model of El Chichón volcano, showing the towns that were completely or partially obliterated by pyroclastic flows and surges produced on April 3, 1982. B) Aerial view of the total destruction of the town of Francisco León and remains of the church. Photograph by Rosa Plá Cortés taken in April 1982. C) Aerial view from the west of the town of Chapultenango, showing the collapse roofs of the church and some houses. Photograph by Federico Fregoso, April 1982.

Most people living in the devastation zone were farmers which are located further away from the volcano than and had agricultural lifestyles. They grew crops of corn, Chapultenango. Tephra fall occurred quickly, blocking beans, cacao, and chile, and raised cattle on fertile pastures main roads and paths and isolating many people who (Espíndola et al., 2002). Towns such as Chapultenango, were unable to flee the volcano. Naranjo, Ostuacán, and Nicapa experienced the damaging effects of ash fall; the roofs of the town church and many Pyroclastic flow deposits blocked the drainage of homes collapsed (Fig. 4). Damage to roofs because of the Ostuacán-Magdalena River to the southwest of the the weight of accumulated ash also occurred widely in volcano. These deposits formed a 25 to 75 m-thick natural the villages of Ixtacomitán, Tectuapán, and Pichucalco, dam that immediately afterward began to develop a

117 Geofis. Int. 48 (1), 2008 temporary lake (SEAN, 1982; Riva Palacio-Chiang, 1983; Location of the study area Macías et al., 2004). In May 26, water of the lake began to spill over the top of the dam, causing its failure and Chapultenango is situated at a moderate elevation the generation of two hot, debris flows, that diluted and of 640 m above sea level (a. s. l.). It is bordered by the merged downstream to become a single hyperconcentrated neighboring counties of Pichucalco and Ixtacomitán to flow (Macías et al., 2004). This flow had a temperature the north; Solosuchiapa and Ixhuatán to the east; Tapilula, of 90°C at Xochimilco, 82°C at Ostuacán, and 50°C by Pantepec, Tapalpa and Ocotepec to the south; and Francisco the time it reached the Peñitas Hidroelectric Dam 25 km León to the west (SEGOB, 1989). Chapultenango county downstream. At Peñitas, the flow generated a large wave has 6,850 inhabitants (49.6% males, 50.4% females), that killed one worker and seriously injured four others. dedicated to rural activities (INEGI, 2000). About 71% of the county’s population is younger than 30 years, with a mean age of 16 years. Our study was conducted in the town of Chapultenango that has a population of 2,794 (48.92% males, 51.08 % females).

Methodology

This study began with semi-structured questionnaires completed by students who did not experience the 1982 eruption and the conduct of interviews with the adults who did. The adult group ranged in age from 26 to 95 years (average 55); the student group ranged in age from 10 to 22 years (average 14). The questionnaire was administered at the students’ schools with the support of teachers and county authorities. To test the efficiency of the questionnaire, we carried out a pilot study involving only 1% of the population. Following the pilot study, the questionnaire was slightly modified before it was administered for the entire sample group. Both the questionnaires and the interviews consisted of two parts—one containing demographic questions, and the other containing questions specific to the volcano.

To obtain statistically valid results, we calculated the minimum sample to be surveyed using the equation (Duffau, 1999):

2 N*Za p*q n = 2 2 d *(N-1) + Za * p* q where:

• N = Total population (2,794) 2 • Za = 2.242 (with a confidence value of 97.5%) • p = expected proportion (in this case 2.5% = 0.025) • q = 1 – p (in this case 1-0.025 = 0.975) • d = precision (we want 2%)

Thus, for a study with 97.5% confidence and 2% precision a minimum sample, n = 275, was calculated:

2,794 *2.242 *0.025 *0.975 Fig. 4. A) Aerial view of the town of Naranjo, located south n = = 275 0.022 (2,794 – 1) + 2.242 *0.025 *0.975 of El Chichón volcano (see Fig. 3). Notice the church with the collapsed roof. B) Close-up view of the church interior. Photo- graphs by Rosa Plá Cortés taken in March 1982.

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We exceeded this minimum sample by studying 300 are Catholics, 9% are Adventist, and a minority (4%) not people, 90 of whom were interviewed (see Appendix A for practicing any religion. Overall, 38% are bilingual; they interview questions), and the remainder (210) answered speak the local Zoque language as well as Spanish. Some questionnaires (see Appendix B). The percentage of 28% have never visited the summit area of El Chichón participants completing questionnaires (70%) correlates volcano, with the lowest percentages among elementary with the percentage of young people (71%) out of the school students. About 30% were aware of the 1982 total population of Chapultenango. Then, the information eruption and its impacts in their surroundings. Among the obtained was processed in a spread sheet and graphically 70% that did not, 12% knew some other details on the (Figs. 5–10). origin of the volcanic activity, 18% mentioned other types of information related to the volcano and its history such Results as legends, 22% described other subjects not relevant to the eruption, and 18% indicated that they do not know Questionnaire Survey of Students anything related to El Chichón volcano. Not surprisingly, comparing the results among the different education All the student respondents were not yet born at the levels it is clear that high school students (44%) know time of the 1982 eruption. The ages of the students range more information about the eruption than do elementary between 10 and 22 years old (14 average), of which 87% and secondory school students.

Fig. 5. A) What and how do you know about the volcano? B) Do you know who can help you in case of a future eruption of El Chichón? Questions asked to students ranging from 10 to 22 years old living in the town of Chapultenango.

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Of the student respondents, 54% fear living close We assessed the levels of the respondents’ knowledge to the volcano, although elementary school students of basic preparedness for a volcanic eruption, and 66% were the most fearful (67% said they feared the volcano of them know the evacuation route, which is the paved compared to fewer percent in the other groups). A similar road connecting Chapultenango with Ixtacomitán and number (56%) stated not having been informed about the Pichucalco towns. However, in case of a future eruption, activity of the volcano (Fig. 5A), This latter percentage only 40% of the students will bring along personal compares well with 65% of the group who believe they belongings such as important documents, radio, flash know who can help them to be better prepared in case lights, and medicine. 28% of the students do not know of a future eruption. 39% of the students will turn to the which type of belongings they should have with them county authorities, as they believe the county authorities (Fig. 6B). are responsible for public safety and are aware of current state of the volcano (Fig. 5B). Surprisingly, 80% of the students sampled believe that the volcano will erupt again, and in such case, 91% will be ready to leave their homes when it occurs (Fig. 6A).

Fig. 6. A) If the volcano erupts, would you go away?

Fig. 6. B) Do you know what belongings you should have in case of an eruption? Questions asked to the student group living in Chapultenango.

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Interviews with adults who experienced the 1982 Of the total sample of those interviewed, 50% were eruption born in Chapultenango, while 44% relocated there from other places after the 1982 eruption. Overall, 87% We carried out 90 interviews with the adults who voluntarily fled the volcano to save their lives, while experienced the 1982 eruption; these respondents ranged 13 % were forced to leave by the Army (Fig. 7A). This in age from 26 to 95 years (average 55), and they were accords well with their statements about the intervention born in Chapultenango or in towns around El Chichón. of authorities during the 1982 eruption, mostly involving Overall, 79% of this group is Catholic and 14% Seventh the National Army (67%) and county government (15%). Day Adventist; the balance does not practice any religion. The displaced villagers became refugees in shelters About 48% are bilingual; they speak the local Zoque located in Chiapas (50%), Tabasco (41%), and other language as well as Spanish. Not surprisingly, levels of places (9%) (Fig. 7B). Half of the population stayed away education in this rural area were not high. About half of from their communities for months (49%), years (29%), the interviewees did not have the opportunity to study in a or days (15%) following the eruption, while some of them formal educational setting. Only 36% started elementary never repopulated their villages (7%) (Fig. 7C). This school, although most of them only attended the first latter number is related to villages that were completely few grades because: the schools were too far from their destroyed by pyroclastic surges and uninhabitable after homes; the family had economic problems; or there was the 1982 eruption because the lands were no longer an absence or scarcity of teachers. In fact, only 4% of productive for agriculture (e.g., Esquipula Guayabal, San the interviewees finished formal schooling. Today, most Pedro Yaspac, Francisco León, Tanchichal, etc). people’s livelihoods are dedicated to agriculture (48%), household (21%), small business (15%), and the rest to One question was asked to help us understand the other economic activities (16%). Today, most houses types of hazardous phenomena that were observed by of Chapultenango are built with concrete walls (75%), villagers during the eruption. The interviewees described bamboo (22%), and wood (3%); and with metal roofs with their own words phenomena such as ash falls (33%. (83%), concrete (15%), and other types of materials rain of sand), pyroclastic flows (20%, fire pouring out (2%). from the volcano), electric storms (11%, thunder and

Fig. 7. Did you experience the 1982 eruption? A) What did you do?, B) To where were you displaced?, C) How long were you displaced from your home? Questions asked during interviews with adults, between 26 and 95 years old.

121 Geofis. Int. 48 (1), 2008 lightning), explosions (18%), lahars (1%, boiling rivers), 11% indicated that they will take their own measures. 8% felt earthquakes, 6% considered other aspects, and Despite the high percentage (82%) reporting that they do the rest did not witness any phenomena (Fig. 8). The not know what to do in an eruption, more than half of eruption caused severe problems for the interviewees, the respondents indicated that they have received volcano including the collapse of metal roofs (40%), destruction information from sources such as the local authorities of crops (28%), loss of cattle and other livestock (24%), (25%), geologists and volcanologists that periodically and, unfortunately, the death of family members during visit the volcano (10%), the media (3%), by their own the eruption (4%) (Fig. 9A). In most cases, the bodies means (13%), and by visiting the volcano themselves of the people killed were never found by the surviving (12%) (Fig. 10). However, 37% said that nobody had relatives. informed them about the volcano, and a similar number (44%) did not know about emergency plans. On average, 47% of the interviewees believed that the volcano will erupt again, but not at time soon—in Finally, the interviewees in Chapultenango affirmed hundreds of years rather than months, years or decades. that, despite the adverse impacts, the 1982 eruption also Some 20% believed that the volcano will not erupt again, brought several benefits to their community, including and 33% did not have an idea of what might happen (Fig. a paved road, services such as telephone, electricity, 9B). etc, as well as natural fertilization of soils by chemical nutrients adhered to the tephra and other socio-economics Some interview questions were posed to obtain the improvements. people’s perception of risk. For instance, 65% of the sample believes that they will be affected by a future Discussion eruption (because they live too close to the volcano), while 35% hold the opposite perception (because the volcano Analysis of results at El Chichón volcano will not erupt again). If eruption should occur, 49% of the people said they will stay in Chapultenango, not Our study presents the first data obtained from a because they do not fear the volcano, but because during social-science study of the community of Chapultenango the 1982 eruption their abandoned or evacuated homes after the 1982 eruption of El Chichón. One of the most and property were looted. The rest (51%) reported that interesting aspects of the survey was to evaluate the they will immediately leave to save their lives and their volcanic hazards and related phenomena witnessed by families. However, these numbers do not correlate with the adult group that experienced the eruption. During the measures they will need to take to protect themselves the March 28, 1982 eruption, this group recognized during the time of an impending eruption, because 82% ash fallout and earthquakes as the main hazards. This of the people do not know what to do. Some 7% indicated observation correlates fairly well with the stratigraphy that they will follow instructions of local authorities while described for this particular eruption, which emplaced

Fig. 8. What types of volcanic phenomena did you observe during the eruption? Questions asked during interviews with the adults group.

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Fig. 9. A) Did the eruption cause damage to you or your family? and B) Do you believe that the volcano will erupt again? Questions asked during interviews with the adults group. a single fallout layer designated “A” by Sigurdsson et of El Chichón, it has a better view of the volcano than al. (1984). However, it is possible that the adult group that from Chapultenango. Thus, people at Pichucalco, at Chapultenango did not recognize other phenomena including most of the adults interviewed, were able to during the March 28 eruption (i.e., lightning, thunder, and witness the 3 April explosion. explosions) because the town does not have a direct line of sight to the volcano and also because of the complete During the April 3 explosion, the adult group chaos that ensued during the eruption in all towns around experienced earthquakes, thunder storms, explosions, the volcano. In fact, 87% of the adults were trying to ash fall, and pyroclastic flows. These hazards were escape by foot to the nearby communities of Ixtacomitán also witnessed and reported by volcanologists of the and Pichucalco. During the following day (29 March), Geophysics Institute of UNAM who were staying in 13% of the adults were evacuated by the Army, and most the town of Ostuacan some days before this cataclysmic of them never returned to their homes. At the time of eruption (personal communication, Servando De la the April 3 explosion, which occurred at night and was Cruz-Reyna). Moreover, days to months after the April 3 the most violent event of the 1982 eruption (Yokoyama eruption, the adult group, other witnesses, and scientists et al., 1992), most adults were at shelters in the town of observed the occurrence of lahars in several gullies around Pichucalco. Even though this town is situated 20 km NE the volcano (personal communication, F. Fregoso).

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Fig. 10. Who inform you about the activity of the volcano? Questions asked during interviews made with the adults group.

As a group, the students are better informed about Since 1982, little to no effective educational the volcano and related activity (82%) than are the information or emergency plans have been given to the adults (43%). About 80% of the students thought that the population of Chapultenango although some information volcano will erupt again because volcanism is a natural has been presented at schools and people have obtained phenomenon, and that the longer it takes to renew its ‘information’ or knowledge through past experiences. activity, the greater the possibility of another eruption. In Johnston et al. (1999) demonstrated that, when a contrast, 53% of the adults thought that the volcano will population perceives its vulnerability to any type of natural not erupt again, perhaps assuming that volcanoes erupt phenomena, it is more likely that they will respond to only once during their entire life span. Some 54% of the warnings of danger and, therefore, respond to preventative students are afraid to live close to the volcano, because measures. Thus, it is important that a comprehensive they believe that, in a future eruption, they will not have educational information program be started to increase enough time to leave their community before being buried the awareness of hazards of people among the populations by ash. In contrast, 65% of the adults are conscious that around El Chichón volcano to increase their ability to their community will be affected by a future eruption, but effectively respond to, or otherwise cope with, the next they are not afraid because they survived the one in 1982. eruption. During the past 10 years, there have been some They now believe they will know what to do and how attempts by scientists to initiate a volcano- monitoring to react in a future eruption. It appears that their beliefs program in the State of Chiapas, to keep the populations about what they should do are based more on their prior and civil authorities around El Chichón informed of the experience with the 1982 eruption or information that volcano’s activity, its hazards, and emergency response they obtained informally since the eruption; a minority plans (Ramos et al., 2007). Unfortunately, these recent of them (25%) indicated they had been informed about attempts do not represent a concerted policy of the preparedness, emergency plans, and evacuation routes. Chiapas State to reduce the threat of volcanic hazards and Students, on the other hand, apparently had received more risk posed by possible renewed eruptions of El Chichón. information than the adults (44%). Thus, it is clear that Underlying causes for the absence of such a policy is the the adults’ thinking reflected experience gained during lack of sufficient financial resources and trained personnel the 1982 eruption, but that does not necessarily mean that to carry out an effective program of volcano monitoring their intentions are what would be desired by authorities. and public education. For example, while 91% of the students said they would evacuate the town in a future eruption, only 51% of the Johnston et al. (1999) reported that people’s knowledge adults said they would leave. Perhaps the 49% of the of a hazard is directly related to the degree of expected adults who stated that they will not leave their homes in maximum hazard, the degree of damage from prior the next eruption reflects their worry that during the 1982 events, and the degree of information available about the eruption they and others suffered at the shelters and their hazard. For Ruapehu Volcano, New Zealand, these authors properties were looted while they were away from their concluded that the perception of risk is linked to people’s homes. proximity to the volcanic center, the likelihood of a future

124 Geofis. Int. 48 (1), 2008 disaster, the impact level, and past disaster experiences studied cases, we note similar results for Colima volcano (Paton et al., 2001). If so, then Chapultenango and (34%). However, both these percentages are lower if they communities around El Chichón represent an excellent are compared to Nea Kameni, Greece (53%) (Dominey- opportunity for such inquiry. These studies have increased Howes and Minos-Minopoulos, 2004). On the contrary, during the last few years, in communities in Kona on the lava flows and gases are perceived as the most dangerous Island of Hawaii (Gregg et al., 2003), Santorini Greece hazards at Monte Columbo and Santorini volcanoes in (Dominey-Howes and Minos-Minopoulos, 2004), Arenal Greece, and Colima volcano, in Mexico (Cuevas and Costa Rica (Acuña and Varela, 2003), and Ruapeu New Ceballos, 2001). Such hazards do not represent threats to Zealand (Johnston et al., 2000). the Chapultenango inhabitants, because El Chichón is not a lava flow producer. Comparison with studies at other volcanoes When people were asked if the volcano will erupt The study of the Chapultenango community at El again, only 47% believed that El Chichón will erupt in the Chichón volcano showed striking results. Some 43% of future. This figure contrasts with the higher percentages the sample surveyed did not even know that El Chichón obtained at Colima volcano (80%), and Mauna Loa (71%), was a volcano—especially a potentially active volcano— Hualalai (66%) in Hawaii. Obviously, these percentages prior to the 1982 eruption. This finding is somewhat reflect the higher eruption frequencies at Colima (Cuevas surprising given the few pre-1982 geological studies and Ceballos, 2001) and Hawaii frequent eruptions (Gregg (Mullerried, 1933; Damon and Montesinos, 1978; Canul et al., 2003) during recent centuries or even decades. and Rocha, 1981) that classified it as an “active” volcano. In comparison, at Santorini, Greece, 93% and 60% of People who live around active volcanoes perceive risk people surveyed knew that the islands of Nea Kameni in different ways. For example, only 6% of the people and Monte Columbo represented active volcanoes, surveyed in Hawaii consider that their community will be respectively (Dominey-Howes and Minos-Minopoulos, affected by a future eruption of Mauna Loa and/or Kilauea 2004); both Nea Kameni and Monte Columbo are island volcanoes (Gregg et al., 2003), this low percentage may volcanoes and this may explain the people’s perceptions. be influenced by the fact that eruptions in recent centuries have been mostly non-explosive (personal comm. Robert Table 1 shows the volcanic hazards that the population I. Tilling). This number increases to 23% at Arenal of Chapultenango perceive as genuine threats to their volcano, Costa Rica (Acuña and Varela, 2003), 65% at El community. These hazards, in order of importance as Chichón, and as high as 80% at Colima Volcano (Cuevas perceived by the people, are: tephra fallout and ballistics and Ceballos, 2001). In case of a future eruption, 49% of (33%), pyroclastic flows (20%), earthquakes (8%), electric those surveyed at El Chichón will stay at their community storms (11%), and explosions (18%). If we compare the analyzing the situation prior to evacuate; similar numbers volcanic hazard considered the most dangerous (33%) at El were obtained at Nea Kameni (46%) and Arenal (49%). Chichón (tephra fallout and ballistic projectiles) with other

Table 1 Summary of the volcanic hazards recognized and described by studied populations, at different volcanoes around the globe.

Volcano/Hazards Tephra Fallouts Pyroclastic Earthquakes Lava Gases Tsunamis Electric Explosions & Ballistics flows flows Storms

Nea Kameni, 53% 62% 44% Greece1

Monte Columbo, 18% 40% 12% Greece1

Volcán de Fuego, 34% 14% Colima2 El Chichón, 33% 20% 8% 11% 18% Chiapas3

125 Geofis. Int. 48 (1), 2008

In terms of public safety and emergency plans, 40% active. They seem better prepared to face the possibility of the people at Arenal volcano and 44% at El Chichón of a new eruption than the adult group, because they know volcano have not heard about evacuation plans, nor the more information from the school, family, the community, location of evacuation routes or shelters. This finding also and the mass media. Should El Chichón erupt again, the applies to the results obtained at Santorini, for a question Zoque community of Chapultenango still remains highly as to whom the population thinks may inform them during vulnerable to the hazards of ballistic projectiles and tephra a volcanic crisis: the county major (44%), the police fall because most houses are made of bamboo walls and (23%), the national government (23%), the army (20%), flimsy metal roofs. and the mass media (12%). At El Chichón, the answers also range widely, with 25% saying county authorities From our study, we conclude that, since the 1982 would alert them, 10% geologists and volcanologists, eruption, little to no effective educational information and 3% the mass media. Some (25%) said by their own or emergency plans have been given to the population of means and 37% indicated that they do not know who Chapultenango. Therefore, we recommend implementing will inform them. Surprisingly, at Popocatépetl volcano, a comprehensive educational information program for the 64% of those interviewed mentioned that the mass media, populations living near El Chichón volcano to increase reflecting the attention posed by the mass media tothe their ability to effectively respond to or otherwise cope Popocatépetl volcanic crisis because its location nearby with the next eruption. This program should include large metropolitan areas as Mexico City, Puebla, Tlaxcala, the county, civil protection and government officials as and Cuernavaca—with a combined total population of ca. well as the scientific community involved in volcano 30 million people. monitoring and hazards studies. Finally, by comparing the results of this social science study at El Chichón volcano, The 1982 eruption of El Chichón volcano represents with similar studies at volcanoes elsewhere, it appears the worst volcanic disaster that has occurred in Mexico that, regardless of the level of educational information in recorded history. Yet, twenty seven years after this provided or extent of response plans in Mexico and other catastrophic event, Mexico still has not been able to countries, the general public’s knowledge of volcanic implement an effective national educational program, hazards varies markedly. capable to operate in a consistent way, for people living around volcanoes. Such a program will be feasible, only Acknowledgments if the local authorities in charge of the civil protection programs are not removed every three years by the county This project was supported by grants from Consejo head in charge. Therefore, scientists and the local civil Nacional de Ciencia y Tecnología (27993-7 to J.L. authorities need to assess the inadequacies of current Macías), CNR-CONACYT Bilateral Project to J.L. policies and practices, to convince the federal government Macías and Dirección General de Asuntos del Personal to modify and further improve efforts to reduce risk from Académico, Universidad Nacional Autónoma de México volcanic hazards. (IX101404 to J.L. Macías). We are indebted to Chris Gregg who provided a careful review of an earlier version Conclusions of the manuscript and helped to clarify ideas. We thank the technical support of A. M. Rocha. We appreciate the The March 28-April 4, 1982 eruption of El Chichón thoughtful reviews of the manuscript by R. I. Tilling and volcano, devastated the surrounding areas; nine towns an anonymous reviewer. were destroyed and more than 2,000 people were killed. People who lost property but survived the eruption Bibliography migrated to other towns near El Chichón, damaged less by the eruption than their towns. One of these towns Acuña, O. and A. Varela, 2003. Análisis de la percepción was Chapultenango. Our interviews with Chapultenango de riesgo en la Fortuna de San Carlos y alrededores. adults (> 26 years old) and questionnaires completed by Universidad de Costa Rica. its students (10-22 years old) evaluated their perception regarding volcanic hazards, risk, and preparedness to Báez-Jorge. F., A. Rivera-Balderas and P. Arrieta- cope with a future eruption. The adult group experienced Fernández, 1985. Cuando el cielo ardió y se quemó and survived the eruption and was aware of pyroclastic la tierra. 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C. Limón-Hernández1 and J. L. Macías1* Departamento de Vulcanología, Instituto de Geofísica Universidad Nacional Autónoma de México Coyoacán 04510, Mexico City, Mexico *Corresponding author: [email protected]

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Appendix A

Interview questions for residents older than 22 years from the town of Chapultenango in May 2004.

Gender: M F Religion: Age: Occupation: Education: Language: Community:

1. Where were you born?

2. What name do you have for the volcano?

3. Do you know any stories or legends about the volcano?

4. What did you think of the volcano before the explosion / 1982 eruption?

5. Why do you think the volcano exploded?

6. Did you experience the 1982 eruption?

7. What did you see during the eruption?

8. Of what were you most afraid?

9. Did the eruption cause damage to you or your family?

10. Did the authorities intervened during the eruption?

11. Was any assistance given to you after the eruption?

12. Do you believe that the volcano will erupt again?

13. Do you think that your community would be affected by another eruption?

14. What would you do in case of another eruption?

15. Do you know if anyone is studying the volcano?

16. Who informs you about the activity at the volcano?

17. Has anyone explained to you the hazards that the volcano poses for you?

18. Have you been informed about what to do in case of an eruption?

19. Do you know if there are shelters and evacuation routes in case of an eruption?

20. In the years since the eruption, have you benefited from the eruption?

21. Does your home have electricity, water and plumbing?

22. What type of material is your roof made of?

23. What type of material is your home made of?

131 Geofis. Int. 48 (1), 2008

Appendix B

Questionnaire for completion by students of the town of Chapultenango in May 2004.

Date:

Gender: M F Community: Age: Religion: Education: Language:

1. Do you know about the volcano? YES/NO

2. Have you visited the volcano? YES /NO Why?

3. What do you know about the volcano?

4. Are you scared of living near the volcano? YES /NO Why?

5. Do you believe that the volcano will erupt again? YES /NO Why?

6. If the volcano does erupt, would you go away? YES /NO Where?

7. Do you have information about the volcano? YES /NO Which?

8. Do you know what belongings you should have ready in case of an eruption? YES /NO What?

9. Do you know who can help you in case of an eruption? YES /NO Who?

10. Do you know the evacuation routes? YES/NO

Make a drawing of the volcano

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